1. Field of the Invention
The present invention relates to wireless communication systems. More particularly, the present invention relates to a method and apparatus of handling in-device co-existence in a multi-radio environment.
2. Description of the Related Art
Coexistence of Long Term Evolution (LTE) with the Industrial, Scientific and Medical (ISM) band technologies, such as Bluetooth, Wi-Fi and the like, and Global Navigation Satellite Systems (GNSS) should be provided as these technologies and systems are becoming very common combinations in User Equipment (UE), such as cell phones, or any other similar and/or suitable electronic device. These technologies may be developed by different groups to serve different purposes, and accordingly, characteristics of each of these technologies may be different. For example, the different technologies and systems may operate in different frequencies, have different access mechanisms, have different frame structures, and peak transmit powers, as well as any other similar differences in operations and characteristics.
An LTE band 7 Uplink (UL) and a Bluetooth band are separated by a 20 MHz frequency band. The LTE band 7 is a Frequency Division Duplexing (FDD) band and hence an LTE receiver is not affected by a Bluetooth transmitter whereas the LTE transmitter may affect a Bluetooth receiver. Also, there is a separation of 2 MHz between an LTE band 40, which is a Time Division Duplexing (TDD) band, and the Bluetooth band. Therefore, it may be difficult to discontinue using a higher portion of the LTE band 40 in a case of coexistence of an LTE system and a Bluetooth system.
FIG. 1A is a schematic diagram illustrating separation between an LTE band and a Bluetooth band according to the related art.
Referring to FIG. 1A, there are 14 channels demarcated in an ISM band for a Wi-Fi operation. Each channel is separated from an adjacent channel by 5 MHz, with an exception of channel number 14 which is separated by 12 MHz. Channel 1 of the LTE band 40 starts with 2401 MHz, and hence there is almost no separation between the LTE band 40 and a Wi-Fi band. Channel 14 of the Wi-Fi band ends at 2495 MHz, so there may only be a 5 MHz separation between an LTE band 7 and the Wi-Fi band. Different countries have different policies for a number of allowed channels of the Wi-Fi band. Currently, many countries allow channels 1 to 13, whereas Japan allows usage of a channel number 14 for IEEE 802.11b based communications. This suggests that, even though in theory there may be only 5 MHz separation between the Wi-Fi band and the LTE band 7, in practice at least 17 MHz is available.
FIG. 1B is a schematic diagram illustrating separation between an LTE band and a Wi-Fi band according to the related art.
Referring to FIG. 1B, in a case of co-existence of an LTE system with a Worldwide Interoperability for Microwave Access (WiMax) system, in-device co-existence interference may exist between an LTE radio entity and a WiMax radio entity when a 10 Mhz band is used for WiMax communication and another 10 Mhz band is used for LTE communication. As the two bands are different, possibility of in-device co-existence interference between the WiMax radio entity and the LTE radio entity is low. However, in-device co-existence interference may arise due to leakage in a radio filter and per-sub-carrier side lobes may not fall relatively slowly.
FIG. 1C is a schematic diagram illustrating separation between the LTE band and the WiMax band according to related art.
Referring to FIG. 1C, the co-existence of the WiMax radio entity with the LTE radio entity is shown. As can be seen from FIG. 1C, a Downlink (DL) part of the WiMax radio entity overlaps with the uplink part of the LTE radio entity, resulting in high amount of interference despite maintaining synchronization between frame boundaries. Accordingly, there is a need for a method and apparatus of handling in-device co-existence in a multi-radio environment.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.